1. Field of the Invention
The present invention relates to novel compounds which are useful as materials for producing polyesters, polyamides, polyurethanes, etc. or as intermediates for tetracyanoquinodimethanes which are expectedly useful as organic semiconductors.
2. Description of the Prior Art
7,7,8,8-Tetracyanoquinodimethane is in the form of yellow crystals melting at 293.5.degree. to 296.degree. C. This compound readily accepts one electron to form a stable anionic radical, and derivatives thereof exhibit very low electric resistance. When reduced with thiophenol, mercaptoacetic acid, hydrogen iodide or the like, the compound is converted to phenylenedimalononitrile, which returns to 7,7,8,8-tetracyanoquinodimethane when oxidized with N-chlorosuccinimide.
It is known to prepare 7,7,8,8-tetracyanoquinodimethane, for example, by subjecting malononitrile and 1,4-cyclohexane-dione to a condensation reaction to obtain 1,4-bis(dicyanomethylene)cyclohexane, and oxidizing the cyclohexane in pyridine with N-bromosuccinimide or bromine.
7,7,8,8-Tetracyanoquinodimethane, although an organic compound, is electrically conductive as already mentioned, so that it is useful to find other processes for preparing the compound or to find electrically conductive compounds resembling the compound in skeleton. Such attempts will be important to the research on and development and application of conductive organic compounds of this type.
Since 7,7,8,8-tetracyanoquinodimethane has a very high melting point as mentioned above and is almost insoluble in organic solvents, these properties are limiting factors to the use of the compound. Accordingly, it is of importance to find analogous compounds free of such drawbacks.